I tried to search in the forum if maybe this topic has been already asked, but the search functionality here is not very user friendly

My situation is the following. I have a report and I want to have three different filters for it.

Initially I was using Javascript filters using GET method, but faced a lot of issues when filtering the third variable.

Now I'm using standard HTML form, but my problem now is that Joomla is overriding the address I'm adding in the Action attribute. I'm adding there the report URL (JUMI URL) but is being replaced by the index.php of the website: